We’ve heard a lot in recent months about an extremely rare blood clotting syndrome linked to the AstraZeneca COVID-19 vaccine, but little has been made about a relatively common side effect of the Pfizer vaccine.

Swelling under the arm is a potential symptom of the Pfizer shot, but has triggered fears of breast cancer among women.

Leanne Wright is senior vice-president of communications at ZoomerMedia.

She shared her experience following her second Pfizer shot, while on Zoomer Radio’s Fight Back with Libby Znaimer.

“It was about two days later, 48 hours later, almost to the minute. I was in the shower, and right under my arm, I discovered a lump that was basically the size of a golf ball,” Wright explained. Listen to the full story by clicking here.

“There are a lot of women experiencing the swelling, even myself I had it,” said Dr. Belinda Curpen, a radiologist in the Breast Imaging Divison of Sunnybrook Health Sciences Centre, on Fight Back, “It’s the normal immune response to a vaccine, and the Pfizer vaccine causes a very intense immune response so it’s actually a good thing. It means that your body is reacting and developing your immune response to COVID-19.”

The underarm swelling typically takes two or three days to go down.